Eugenia Picano

CT Colonography: Role of a second reader CAD paradigm in the initial training of radiologists

PURPOSE To evaluate the influence of CAD for the evaluation of CT colonography (CTC) datasets by inexperienced readers during the attendance of a dedicated hands-on training course. METHOD AND MATERIALS Twenty-seven radiologists inexperienced in CTC (11 with no CTC training at all, 16 having previously reviewed no more than 10 CTC cases overall) attended a hands-on training course based on direct teaching on fifteen workstations (four Advantage Windows 4.4 with Colon VCAR software, GE; six CADCOLON, Im3D; five ColonScreen (Toshiba/Voxar) with ColonCAD™ API, Medicsight). During the course, readers were instructed to analyze 26 CTC cases including 38 colonic lesions obtained through low-dose MDCT acquisitions, consisting of 12 polyps sized less than 6 mm, 9 polyps sized between 6 and 10 mm, 12 polyps sized between 11 mm and 30 mm, and 5 colonic masses sized>3 cm. CTC images were reviewed by each reader both in 2D and 3D mode, respectively by direct evaluation of native axial images and MPR reconstructions, and virtual endoscopy or dissected views. Each reader had 15 min time for assessing each dataset without CAD, after which results were compared with those provided by CAD software. Global rater sensitivity for each lesion size before and after CAD usage was compared by means of two-tailed Students t test, while sensitivity of each single reader before and after CAD usage was assessed with the McNemar test. RESULTS For lesions sized<6 mm, global rater sensitivity was 0.1852±0.1656 (mean±SD) before CAD-assisted reading and 0.2345±0.1761 after CAD (p=0.0018). For lesions sized 6-9 mm, sensitivity was 0.2870±0.1016 before CAD-assisted reading and 0.3117±0.1099 after CAD (p=0.0027). For lesions sized 10-30 mm, sensitivity was 0.5308±0.2120 before CAD-assisted reading and 0.5637±0.2133 after CAD (p=0.0086), while for lesions sized>30 mm, sensitivity before CAD-assisted reading was 0.3556±0.3105 and did not change after CAD usage (p=1). Sensitivity of each single rater did not significantly differ before and after CAD for any lesion size category (McNemar test, p>0.05). Specificity was not significantly different before and after CAD for any lesion size (>96% for all size categories). CONCLUSION CAD usage led to increased overall sensitivity of inexperienced readers for all polyps sizes, except for lesions>30 mm, but sensitivity of individual raters was not significantly higher compared with CAD-unassisted reading.

Time-resolved contrast-enhanced magnetic resonance angiography (CEMRA) of the left atrium–pulmonary veins complex with half dose of intravenous gadolinium-based contrast agent. Technical feasibility and comparison with a conventional CEMRA, full contrast dose protocol

PURPOSE To evaluate feasibility and image quality of time-resolved contrast-enhanced magnetic resonance angiography (CEMRA) of the left atrium-pulmonary veins (LA-PV) complex with half dose of intravenous gadolinium-based contrast agent (GBCA) in patients candidate to percutaneous radiofrequency ablation of atrial fibrillation. METHODS AND MATERIALS Fifty-seven patients underwent CEMRA of the LA-PV complex on a 1.5T MRI scanner. On 24/57 patients, a conventional fast-spoiled gradient-echo (FSPGR) CEMRA acquisition was run using 0.2 mL/kg of 0.5M GBCA at 2 mL/s flow rate (protocol A), while in 33/57 patients a time-resolved multiphase CEMRA sequence (Time-Resolved Imaging of Contrast KineticS, TRICKS) was performed after intravenous injection of 0.1 mL/kg of the same GBCA at 3 mL/s flow rate (protocol B). Contrast enhancement was measured in the LA (LAe) and in the PA (PAe), and the LAe/PAe ratio was calculated. Diagnostic quality of Maximum Intensity Projection (MIP), Volume Rendering (VR), and Virtual Endoscopy (VE) reconstructions was also assessed visually using a semiquantitative score. RESULTS LAe was comparable with both protocols, while PAe was lower with protocol B than with protocol A (p = 0.0217). Moreover, the LAe/PAe ratio was significantly higher with protocol B than with protocol A (p = 0.0044). Finally, image quality of MIP, VR, and VE reconstructions was significantly better with protocol B than with protocol A (p = 0.0005, p = 0.0001, and p = 0.005, respectively). CONCLUSIONS CEMRA of the LA-PV complex is feasible with TRICKS and half-dose GBCA and yields better separation between the LA-PV complex and the PA, as well as better image quality of MIP, VR, and VE reconstructions than a conventional FSPGR sequence performed with full GBCA dose.

Magnetic resonance (MR) features in triple negative breast cancer (TNBC) vs receptor positive cancer (nTNBC)

Few reports in literature describe triple negative breast cancer (TNBC) imaging findings. Aim of the study is to determine MR-features of TNBC compared to receptor positive cancer (nTNBC). From May 2014 to May 2015, we retrospectively enrolled 31 consecutive patients with histological diagnosis of TNBC and a control group of 31 consecutive nTNBC observed in the same period, out of 602 cancer, diagnosed in our department in the same year. Histopathological analysis and MR-features of TNBC (31 patients) were compared to nTNBC (31 patients). MR-features included dimension, fibroglandular tissue (FGT), background parenchimal enhancement (BPE), mass shape, margins, presence of rim, intratumoral signal intensity in T2w, uni-multifocality, kinetic curves. All patients were examined with MR 1,5T (Magnetom Simphony Tim, Siemens Healthcare) performing T2w fat-sat and contrast enhanced high temporal and spatial resolution T1w before and after injection of Gadolinium. 62 staging MR were reviewed. Median age was 50 (30-78ys) with a standard deviation of 10,9. TNBC showed 3 MR features in concordance with current literature: rim enhancement, hyperintensity in T2 sequence and unifocality. Rim enhancement was shown in 67.7% of TNBC (21/31) and 29% of nTNBC (9/31). Higher T2w values were shown in 83.9% of TNBC (26/31) and 58.1% of nTNBC (18/31). Cancer was multifocal in 7/31 (22.6%) of TNBC and 19/31 (61.3%) nTNBC. No correlation was found for dimension (p=0.12), FGT (p=0.959), BPE (p=0.596), homogeneity of enhancement (p=0.43), margins (p=0.671) and kinetic (p=0.37). Multivariate analysis demonstrated that rim enhancement and unifocality correlated independently with TNBC group. Area under ROC curve of our model is 0.835. Furthermore, we evaluated the clinical outcome of all 31 TNBC patients in a follow-up time ranging from 24months to 36months separating them in a free-survival group (23 women) and a recurrence group (8 women with local recurrence or distant metastasis): only kinetic curves resulted to be significantly higher in recurrence group (p=0.042).